The present invention relates to a joint device suitable for use as legs or arms of an industrial robot.
Facilities such as tower tank, nuclear reactor, fusion reactor and shielding cell in a nuclear fuel reprocessing plant have neither entrance nor space large enough to allow technical personnel to enter or work in and contain harmful radioactive rays and the like. Therefore, it is usually impossible for personnel to enter directly inside these facilities to check them or work in them. With these facilities, it is necessary that the working person be located at a safe site and remotely operate an industrial robot arranged in these facilities or be allowed into them through a small entrance to check or work in them.
This industrial robot must be provided with joints with high freedom in movement for directing a inspection television camera, or the like, attached to the ends of the robot's legs or arms. The TV camera must be able to be moved in any direction or to be set in any position in a small space. Conventional robots employ a combination of rotation joints and pivot joints. Conventional joint devices which allowed rotation, up-down and right-left rocking movements to be achieved through one joint employed a plurality of bevel gears and shafts and therefore became complicated in structure and large in size.